Installation, Operation and Maintenance Manual
Field Installed Variable Frequency Drives (VFD’s
7
Subject to change without notice.
120.7-IM (1218)
Field Provided VFD / Field Installed
(Continued)
8.
Attach the appropriate size wire to the circuit breaker
and connect them to the terminals on the VFD marked
for Mains (L1, L2, & L3) (Refer to Figure 2A or 2B)�
9.
Attach the appropriate size wire to the circuit breaker
and connect them to the terminals on the entering
power block marked for power entering (L1, L2, & L3)
(Refer to Figure 2A or 2B)�
10.
Secure all wiring�
11.
Replace access panel back on the evaporator section�
12.
Turn on power to unit�
13.
Program VFD per the manufacturers instructions�
Static Pressure Transducer
Field or Factory Provided/Field Installed
ELECTRICAL HAZARD
Only a qualified licensed electrician or
other individual that is properly trained in
handling live electrical components should
perform any installation, adjustment,
repair or maintenance� Failure to follow all
electrical safety precautions and industry
accepted practices when exposed to
live electrical components could result in
death or serious injury�
INFORMATION
Use Copper Conductors Only� Failure
to use copper conductors may result in
equipment damage�
The Static Pressure Transducer (SPT) is field installed
external to the main electrical panel and wired back to the
VFD�
1.
Mount the transducer in a vertical position, making
sure that the pneumatic tube connections are at the
bottom� This helps to prevent moisture from reaching
the transducer�
2.
Attach field supplied pneumatic tubing to the “HIGH”
connection of the transducer � (Refer to Figure 3)
3.
Route the pneumatic tubing to a point approximately
2/3rds of the distance down the straightest length of
supply air ducting� Make certain that there are no kinks
in the tubing� Use clamps to hold the tubing into place�
4.
Drill a clearance hole into the center face of one side of
the duct work�
5.
The end of the pneumatic tubing must be cut square to
the tube side wall for the tube to pick up the correct air
pressure reading�
6.
Insert approximately 1/8” of the tubing into the duct.
Make sure the tubing is positioned in the duct at a right
angle so that the air flow goes across the square end of
the tube�
INFORMATION
Damage to the Static Pressure Transducer
may occur if not wired correctly�
7.
Terminals are type sensitive. Power input to the “+”
terminal must be 10 VDC. Output from the “-” terminal
is 4 20 mA to the VFD analog input�
8.
Use 18 AWG wire size to connect from the () and (+)
terminals of the pressure transducer back to the VFD�
(Refer to Figure 3)
9.
The terminal markings on the VFD can vary from one
manufacturer to another� Refer to the VFD manufactur
er instructions for the proper terminal connections�
10.
Static Pressure Transducers are typically preset to read
from O” to 2.5” W.C. The VFD controller will read the
preset configuration and will accelerate or decelerate
the motor to maintain the programmed configuration.
Figure 3 - Static Pressure Transducer
